1. Field of the Invention
The present invention pertains to a survey system and method utilizing one or more field survey instruments adapted to transmit readings and receive data and instructions via a field terminal and radio transmitter and multiplexer and a radio modem linked to a remote central processing unit for comparison of measured survey points with predetermined survey data in accordance with requirements for certain tasks such as in reclaiming surface mined lands and in preparing surface minable lands for removal of overburden.
2. Background
In certain survey operations a substantial number of survey points must be obtained and compared with a predetermined or prescribed topography or a set of predetermined survey points for carrying out certain excavating operations. For example, in surface mining operations, the requirement to restore or reclaim the earth's topography in a particular region which has been mined requires a relatively precise grid of survey points defining surface contours which must be adhered to by the miner after the ore has been removed from beneath an overburden layer. Still further, in surface mining operations it is often necessary to provide a large number of survey points for guiding excavating apparatus or for carrying out blasthole drilling operations with some precision. Movement of large amounts of earth material in surface mining and construction operations by a technique known as blast casting requires relatively precise survey operations for locating the position and direction of drilled blastholes.
Although automatic survey instruments are known in the art which accurately and quickly provide direction, distance and elevation readings of a point, heretofore in field operations it has been necessary to compare the values read by the instrument with tables carried into the field either in printed form or stored in a portable digital computer. The values read by the survey instrument are then compared with the prescribed values for the point being surveyed and corrections are relayed by the instrument operator via portable radio or other signalling means to the operator of the survey rod at the point in question.
For example, in adhering to predetermined survey grids for reclaimed lands which have been surface mined, data prescribing the locations of points on the grid may be stored on portable digital computers which can be taken into the field. To confirm the proper contouring of the land by earth moving equipment, it is necessary to verify the work in progress of a reclaimed surface.
Accordingly, a surveyor surveys predetermined points to obtain the so-called x, y and z values (Northing, Easting and elevation) of the points, record the survey instrument readings and hand enter those values into the computer. The computer is, in many instances, adapted to then compare the position of a particular point with the predetermined required position and provide a reading to advise the surveyor if the elevation of the actual point, for example, is "high" or "low". The surveyor then marks a stake with information to provide either cutting or filling of earth material and then moves to another point.
Since the readings of the survey instrument are required to be manually entered into a computer, each survey team is required to have its own computer and there are many chances for error in transferring the information. The rigorous requirements of field use in surveying is also not conducive to the relatively fragile structural features of many commercially available computers.
Accordingly, there has been a need to improve the accuracy and speed with which field surveys may be conducted of reclaimed lands, prescribed surface contours, and other survey operations, particularly those carried out in large surface mines. It is to this end that the present invention has been developed with a view to providing a system and method which includes a remote, permanent position for a central processing unit or computer for storing and providing data for predetermining the location of survey points and for improving the accuracy and speed with which surveys which require a large number of data entries are carried out.